HOUSTON -- It is called the Texas Chicken, an intricate dance step that requires two partners to race head-on at higher than normal speed, then veer to the right at the last second to avoid colliding. The participants in this craze, however, are 60,000-ton ships and oil-laden tankers winding through the narrow Houston Ship Channel.

Also called the Suez Maneuver because it was developed to navigate the Suez Canal, the procedure occurs as often as 20 times a day along the 25-mile channel that empties into Galveston Bay. Seemingly dangerous, it actually is a safety step, according to ship pilots who practice it, because as a ship plows through the channel, it pushes out the surrounding water and creates a bow wave that keeps the ships apart.

But on July 28, an oil tanker finishing the Texas Chicken collided with two oil-laden barges, spilling 700,000 gallons of oil into the bay in the second of the area's three major oil spills this summer.

"Those are just the substantial ones," said Richard Townsend of Vienna, Va., a marine environmental consultant. "You can bet you had dozens or hundreds more smaller spills that the papers don't report. Those little ones add up."

On June 8, the Norwegian supertanker Mega Borg caught fire and dumped 3.9 million gallons of oil off Galveston. And on Aug. 12, a barge spilled 20,000 gallons of heavy fuel oil.

According to the Coast Guard Office of Marine Safety in Houston, 273,450 gallons of oil spilled into the channel area in 1989. Of the 215 spills last year in the channel, all but one were considered minor because less than 10,000 gallons of oil were dumped.

More than 2 million barrels of crude oil enter Texas ports daily, and the channel area is the world's second largest petrochemical complex. The waterway is lined with petroleum refineries that handle 33.2 million tons of petroleum and petroleum products annually. It is the nation's third-busiest port and, at its widest point, 400 feet, it is 40 feet deep.

Ships passing through the channel average 100 feet in width and must travel around heavy barge and tow traffic near the shore. With docked ships lining the channel's banks, dangerous maneuvers such as the Texas Chicken often are the only way that two large ships can pass. Sometimes, only a 50-to-100-foot margin remains between the two massive, speeding ships.

Pilots, who undergo two years of arduous training specifically for the channel, guide all ships in and out of it. One of the 57 pilots in Houston boards a ship as it leaves port and guides it into the open sea, a five- or six-hour trip. The pilot then descends a rope ladder to a waiting boat that returns him to port. The procedure is reversed for incoming ships.

"Every channel is unique, and the uniqueness of this one is its density," said pilot Harry Lydick, who has navigated the channel since 1976. "It's not the kind of job where you sit back and kick your feet up. It's considered one of the hardest channels in the U.S., if not the world."

The narrow channel and heavy traffic are the principal reasons that Houston voters last fall approved a $130 million bond measure to finance the local share of a $319 million project to widen the channel to 530 feet and deepen it to 45 feet. The Port of Houston Authority boasts that the project will pump $2.5 billion into the local economy and create 9,000 jobs by the year 2025.

Since 1836, when the first steamboat chugged up Buffalo Bayou, as the channel was known then before it became the major route for cotton to the port of Galveston, the waterway has been Houston's economic lifeline.

The devastating hurricane in Galveston in 1900 and the Spindletop oil discovery in nearby Beaumont a year later made Houston an overnight boom town. The first channel was built by the Army Corps of Engineers and opened in 1914. It was deepened to 32 feet in 1932 and in 1967 reached its current depth.

"One major reason for widening the channel is safety," said Lee Vela, media director for the Port of Houston Authority. "The other is economics. A deeper channel means more competitively priced water transportation. We have to modernize. Otherwise, we move backwards."

While a wider channel may allow safer passage, a deeper channel allows heavier loads.

Environmentalists, however, have expressed skepticism about possible economic advantages and concern about harm to the environment. Plans to enlarge the channel are contingent on a four-year environmental study headed by the Corps of Engineers.

Deepening and widening the channel will not increase safety, according to Linda Shead, executive director of the Galveston Bay Foundation, and may lead to serious damage to the bay.

"Our first concern is the salinity balance," she said. "The bay is a balanced mixture of salt and fresh water. Anything that upsets that balance will endanger the marine life . . . and deepening the channel will allow more salt water to come in on a lower level.

"The second major concern is toxics. A lot of toxic wastes have been discharged into the channel."

If wider ships are allowed into a wider channel, Shead said, maneuvers such as the Texas Chicken still would be necessary, and the possibility of larger oil-laden tankers creates the opportunity for even larger spills.

Shead said she agreed with the Texas Railroad Commission and 18 major oil companies that an offshore oil terminal would decrease such accidents, allowing supertankers to unload directly into a pipeline. Such terminals have unloaded about 1 million barrels of crude oil daily without a major spill in nine years.

Critics of the channel project also said spill-prevention measures should be strengthened, perhaps by making it mandatory that ship pilots comply with the Coast Guard's Vessel Traffic Service (VTS).

The VTS, similar to air-traffic control towers, is equipped with radar screens and video displays to help in guiding ships through the channel, but pilots are not required to use it. Authorities said the VTS has a five-mile "dead zone" in the channel that is not covered by cameras or radar.

"If safety in the channel is really so critical, why should we wait for a larger channel?" Shead asked.

Many observers agree that a wider channel will not mean the end of such maneuvers as the Texas Chicken.

"Widening it probably won't reduce the need" for the Chicken, "but it might modify it or make it safer," said Ed White, a public affairs officer with the Corps of Engineers. "But anytime you have two ships going head-on, there is the potential for disaster."